The invention relates to a sealing system consisting of a first part and a second part and at least a passage opening extending in both parts, in particular a passage opening for fluids such as hot combustion gases from combustion engines as well as a corresponding metallic flat gasket.
In the state of the art, on the one hand metallic flat gaskets are used between both parts which rest essentially with their full surface on both parts. The passage openings are then surrounded by elastic sealing elements, in most cases beads which are immediately formed into the metallic layer. They can be in the main force load so that they experience full compression, or they are in the secondary force connection, which is either realized by installation in a groove or by the integration of a deformation limiter in the gasket, so that they can only be compressed to the depth of the groove or to the effective height of the deformation element. This way, it is ascertained that the bead is preloaded in its elastic range only and even under load cannot get out of the elastic range.
With an installation over their full area, these gaskets always also comprise passage openings for fastening means, thus they are fastened between the two parts to be sealed against each other by screwing. One disadvantage resulting from this is the considerable demand in material as the gasket extends over a considerably large area compared to the actual area of the sealing lines. With parts showing several passage openings, an essential problem of this kind of gasket results from the different coefficients of thermal expansion of the parts to be sealed and the gasket. During a cold start in winter, thus e.g. at −20° C. the system shall be tight in the same way as after a longer operating phase with operation temperatures of more than 800° C. or with turbochargers of even 1000° C. This is counteracted by the large sections of material of the gasket connecting the passage openings which encounter different expansion than the parts to be sealed. The positions of the passage openings are thus shifted against each other which results in tensions and/or non-tightness. In addition, the adaptation to the movements of the sealing gap is strongly limited.
In addition, tubes with circumferential sealing structures are known from the state of the art. They seal the different passage openings independent of each other. They are however very complex in their production and often show precision problems. In particular, the production of the radially extending structures is very sensitive and often, small deviations in the dimensions of the part or of the sealing structures lead to considerable problems. Further, the gaskets are exposed to hot and aggressive fluids, in most cases combustion gases, over their entire length. In order to prevent corrosion, it is therefore necessary to use high-grade and therefore expensive materials. If both parts to be sealed move with a different degree, with multi-flow transitions, a destruction of the sealing pipes occurs as they cannot follow this movement.
Further, annular gaskets with c-, <- and ε-shaped profiles are used for the sealing of such sealing systems. They can however only be produced with considerable effort. For a seamless production, a multi-step process is required which further leads to an extreme deformation of the material. As an alternative, production from a flat metal sheet which is then closed to a ring is possible, but even with an extreme treatment always results in an inhomogeneity at the connection portion which can act as a rated break point and further can cause leakages. Further, these c-, <- and ε-profiled rings can only be produced in circular embodiments due to the rolling process finishing the production.